Publication

Application

Priority

RU 9700140 W 19970506

Abstract (en)

The method includes radiating an RF signal within a time Tt, receiving a reflected signal within a fixed time Tr equal in duration to the fixed time Tt of the radiated signal plus a delay tau d between the end of the signal radiation and the beginning of the reflected signal reception. Once a modulated component of a human's heart rate and/or breathing frequency is detected, a level of the component is measured and the reception time of the reflected signal, is modified. This modification is carried out until the level of the modulated component decreases relative to the level of the initially reflected RF signal and until the moment when the signal stops coming in. A distance is further determined from the reception time of the reflected signal with the modulated component. The method can be implemented using a microwave locator comprising a modulator (1) and a transmitter (2) which includes an oscillator (3), a power splitter (4) and a transmitting antenna (5). A receiver (6) comprises a receiving antenna (7), a microwave receiver (8), a preamplifier/demodulator (9) and a signal processing unit (10). The modulator (1) is tunable to modify the duration of control pulses and to lock them. The apparatus further includes a first pulse modulator (11) in the transmitter (2) and a second pulse modulator (12) in the microwave receiver (8). The modulator (1) has a control output which is connected to a control input of the second pulse modulator (12) so that the receiver (6) receives the reflected signal with a delay relative to the end of the signal radiation by the transmitter (2), and the enable time of the microwave receiver (8) is modified. The signal processing unit (10) is adapted to measure a level of the modulated component. <IMAGE>